I also have a green passport, issued mid 93. Never had anyone doubt its authenticity.

I have nearly finished filling my sixth insert. I always get my pages added at the US Embassy in BKK. I have never had to wait more than 5 minutes. The last time however, they wanted to issue me a new passport because they said that my passport was too thick, and they felt that some countries (they quoted China as an example) might think that something was amiss. Since people do cut select pages out of their passports, it becomes difficult to detect whether a passport has been tampered with when it jammed full of inserts. In any event, I declined their offer, as I have numerous active long-term visas that would become invalid once the passport was cancelled upon issuance of a new one. Don't believe U.S. Passport agents when they tell you that you can use 'unexpired' visas in an old passport, if it is presented along with the new one. That strategy only works in some countries.

greg99, I travel to various Gulf states on occasion, and also have a second passport due to travel to Israel. (I used to get Israelis stamps on a separate loose page, but for several reasons, now have the stamps placed directly into my passport.) When renewal time came, I actually had a bit of a hassle renewing it in BKK. Now, I renew it only in the U.S.